Tsuna, the next day, arrives downstairs and greets Iemitsu, Nana, and Colonnello, the aforementioned three greeting him back. Tsuna sees Basil tossing Lambo and I-Pin up and down with a troubled face. Iemitsu asks Tsuna why he looks so preoccupied, Iemitsu himself wondering if it is the "sorrows of love", Reborn wondering if it is unfinished homework, and Colonnello wondering if his stomach hurts. Tsuna sees Iemitsu wearing his Rainbow Wristwatch and suddenly leaves. Nana prepares to scold Tsuna, but Iemitsu stops her, stating that it is his fault for being away from home for so long. As Tsuna leaves, Reborn catches up to Tsuna, telling him to relax about the Representative Battle of the Rainbow. Tsuna expresses his worry, wondering why he is the only one wearing the Boss Representative Rainbow Wristwatch. Tsuna recalls Dino telling him that Dino himself and Reborn discussed it, and decided that Tsuna would be the best person to be the Boss Representative.
Tsuna then runs into Gokudera, Yamamoto, and Ryohei, all three expressing their excitement for the upcoming battle. Tsuna comments that normally walking to school makes the world feel at peace. At school, Tsuna relievedly notices Enma nervously brooding, then brightening up when seeing Tsuna. Tsuna notices Chrome wearing a medical mask, wondering if she caught a cold. The day passes by, Yamamoto commenting that it was uneventful, Tsuna also wishing that the rest of the day would remain the same. Tsuna cheerfully walks around the school, but his Boss Rainbow Wristwatch suddenly beeps, announcing that in one minute, the first round of the Rainbow Battle would commence, Enma, Gokudera, Yamamoto, and Skull all receiving the same message. The clock begins calling out the time, with 50 seconds left. Two shadowy figures arrive at the school. 20 seconds remain. Yamamoto and Ryohei rush away from their events. The countdown then ends, the battle commencing; the watch announces that the time limit was 10 minutes. At Tsuna's location, a Dying Will Flame breaks the wall. Knives are thrown at Enma, but he uses Gravita della Terra to stop the Knives. Belphegor laughs, commenting that Enma was "small fry". Superbia Squalo tells the rest of the Varia to head somewhere else. At Tsuna's location, through the wall, Iemitsu walks through, firmly stating that what brought him home was work, and states to Tsuna that it was about time he started treating him as an adult. Tsuna expresses his shock.
Note: Bold + Italicized = First Appearance